The overall objectives of this project are the refinement of ultrasonic motion imaging of the heart by processing ultrasonic echoes, the development of methods for two- and three-dimensional motion imaging of the heart, and the simultaneous display of structure characteristics and intracardiac blood flow patterns. A 4-element array using hemispherical radiators is under development for three-dimensional image reconstruction of the heart. Computer simulation of beam patterns and investigations of sensitivity are in progress. An algorithm for adaptive control of the ultrasonoscope receiver gain has been developed. It is currently being implemented in software and will require investigation to realize the optimal combination of the rate of convergence and step size for imaging moving targets. Signal processing has been applied to one- and two-dimensional ultrasonic cardiac studies to evaluate left ventricular hypertrophy, experimental myocardial infarction, signal fluctuations resulting from structure change during the caridac cycle, and spatial distribution of frequencies by means of two-dimensional Fourier transforms. Doppler analysis of turbulent flow patterns, based on detection of scattering from flowing particles, has undergone theoretical analysis and indicated equipment modification has been initiated. BIBLIOGRAPHIC REFERENCES: Gramiak, R., Waag, R. C., Nanda, N. C., and Astheimer, J.: Computer processing of cardiac ultrasound images. Presented at the World Federation of Ultrasound in Med and Biol, San Francisco, Ca., 3-7 August 1976. Ultrasound in Med, Vol 3B, White, D. N. (editor), New York, Plenum Press: 1977, in press. (Summary). Waag, R. C., Gramiak, R., Lerner, R. M., Lee, P. P. K., Hunter, L. P., and Schenk, E. Presented at the World Federation of Ultrasound in Med and Biol, San Francisco, Ca., 3-7 August 1976. Ultrasound in Med, Vol 3B, White, D. N., (editor), New York, Plenum Press, 1977, in press. (Summary).